Learn about Aquarium Wet Dry Filters

Wet/dry filters are the highest quality aquarium filters. They are most often used by the advanced hobbyist who wants to keep the most sensitive species. Saltwater fish and reef inhabitants must have the most stable water conditions possible to survive and thrive.

However, if more hobbyists understood how aquarium wet dry filters work, they would become a standard for all aquarists who want to keep more fish and more sensitive fish, and who want to reduce their maintenance to a minimum.

The ocean is a very stable water environment by virtue of the fact that it has such a vast amount of water. The temperature changes are very gradual. The quality of the water changes imperceptibly over time.

More water volume means a more stable tank environment. Less maintenance, healthier fish.

One of the keys to simulating that stable environment in your aquarium is to increase in the quantity of water. More water changes more slowly. Certainly, you can purchase a larger aquarium. However, it is less expensive, and takes up less room to install a water expansion chamber UNDER the aquarium, hidden in the stand. You might be able to nearly double the volume of your aquarium water without increasing the size of your tank. (refugiums)

Essentially that is what a wet dry filter is: A clear acrylic chamber (a sump) that holds water and all of the elements to clean the water in your aquarium - all housed out of sight.

All wet dry filters accept water from your aquarium via a trickle-down device. When the water enters the filter, it passes through media chambers that hold the elements necessary for cleansing the water of its pollutants.

The water is passed over the media by means of a directed trickle or a rotating spray bar that disperses it to drip through the first mechanical filter: a filter pad that traps large particulates and debris.

From there it goes through a media that pulls out colors, odors, medication, and other organic compounds: usually a carbon chamber or pad used for chemical filtration.

Wet/Dry filters offer nearly unlimited biological filtration by expanding the water volume and the volume of media used by colonizing beneficial bacteria.

The HUGE advantage of wet dry filters is their biological chambers. Most contain a filter compartment that houses media supporting aerobic bacteria: The type of oxygen-loving bacteria that literally digest the ammonia and nitrites in your tank, which kill the inhabitants.

The water continues through the chemical filtration media and drips down (collecting oxygen as it goes) to the biological filtration chamber. By the time it reaches the biological chamber or wheel, it is oxygen-rich and organic-compound-and-particulate-free. The oxygen feeds the bacteria, keeping it healthy and reproducing. The bacteria do their magic. And ammonia and nitrite are turned to nitrate.

The perfect balance is maintained between the amount of pollutants the tank produces and the amount of bacteria the filter produces in order to process the pollutants.

Clean water is returned to the tank by means of a submersible pump that pumps it back up to the tank.

The maintenance of a wet/dry filter is reduced compared to other types of filters, and the filter itself is out of site under the aquarium.

Maintenance is reduced because the volume of water has been enlarged, thus reducing the percentage nitrate content. Fewer water changes and less "fiddling" with the media.

The filter is hidden from view and generally contains enough sump space to house your heater right in the filter sump and out of the aquarium's panoramic view. Many wet dry filters also contain protein skimmers or you can add one. You can plumb a UV sterilizer right into the pump-return. All of this additional equipment (while not critical) will greatly enhance your aquarium's stability, save your fish, and reduce your maintenance time and workload. And none of it will be cluttering your relaxing view.